1. Field of the Invention
The invention generally relates to a display and a light source module, and more particularly to a touch display apparatus and a backlight module.
2. Description of Related Art
With the advancement of optoelectronic technologies, a user may no longer be satisfied with controlling a computer and objects on screen through a mouse. Accordingly, more user-friendly interface techniques than the mouse have been gradually developed. In the intuitive techniques, a finger-controlled touch interface commanding the computer approximates the natural experiences of human users.
In conventional techniques, a plurality of methods for implementing the touch interfaces has been provided. For example, in 2007 Microsoft Corp. provided a touch controllable computer allowing the user to operate the computer without using a mouse or a keyboard. Instead, the user moves or taps a finger on a table to operate the computer. The touch controllable computer provided by Microsoft mainly includes a plurality of detection cameras, a projector providing a set of projection images, and a set of infrared light sources. The projector projects images onto the table. When a finger or an object touches the screen, the cameras located under the table detect the reflected infrared light from the finger or the object, thereby judging the locations of the finger gestures and the object.
However, since multiple detection cameras, as well as the projector providing the set of projection images, and the infrared light sources are placed inside the table, the entire device is overly bulky, therefore restricting the range of applicability. Even if the components under the table are packaged together, the user, when seated, may not extend his legs because the space near the knees is limited.
Another conventional technique provides that infrared light sources and optical detectors are disposed on an outer frame of a display panel. When a finger touches the display panel, the finger obstructs a path between the infrared light sources and the optical detectors. Accordingly, a dark spot is generated in the images formed on the optical detectors. By deciphering the locations of the dark spots in the images, a relative position of the finger with respect to the display panel is determined. However, this method of determining the finger touch locations by calculating the finger position obstructing the infrared light is not suitable for multi-touch or touch input from multiple users.
In addition, Taiwan Patent No. M355612 provides a table having a touch display screen, the table including a table body, a computer, a short range projector, a plurality of infrared sources, reflection mirrors, infrared cameras, speakers, and a heat dissipation module. The table body has a table surface and a projection screen. When the user touches the screen, the infrared light incident at the touch point is reflected. In a captured image by the infrared camera, a bright spot is formed at the touch point, and is then used by the computer to determine the position of the bright spot.
Taiwan Patent No. M358989 provides a light guide plate, and U.S. Pat. No. 6,867,828 provides a backlight module. U.S. Pat. No. 6,690,363 provides a touch screen, including a display screen for display of data, a plurality of energy transmitters, and a plurality of detectors for detecting energy. U.S. Pat. No. 6,836,367 provides a touch screen including an optical transmitter, a reflection device, an optical receiver, and a driving unit. In this disclosure, the optical transmitter and the optical receiver are arranged along the two neighboring sides.